DE19916710B4 - Tool drive device, in particular for machine tools - Google Patents

Abstract

Tool drive device (1), in particular for machine tools or machining units in machining centers, each having at least one movably mounted machine spindle,
a spindle insert (2) comprising a coupling device (3) connectable to a machine spindle, a housing (2), a controllable drive (9) for driving a tool adapted to convert its feeding energy into mechanical energy and at least one Supply line (8), which serves to transmit the feed energy to the drive (9) and one or more slip rings (8a, 8b, 8c) which are mounted on the outside of the housing (2) and electrically isolated from this,
a coupling means (11) containing one or more contacts (32) connectable to and separable from the slip ring (s) (8) to make or dissolve an energy transferring connection between a supply source and the drive (9); and with a control device (36) which is set up to drive the drive (9).

Description

The The invention relates to a tool drive device, in particular for the Use in machine tools or machining units of machining centers is set up and each at least one movably mounted Have machine spindle.

Especially for machining tasks Machine tools, for example, used for drilling, turning, milling, etc.

The Tool is inserted into a corresponding tool holder, attached in the work spindle of the machine tool in question becomes. There are different tool holders available.

During the Machining operation are the work spindles of associated drive devices driven. For controlling the spindle movement, in particular its Rotation and / or adjustment, serve control devices, the advanced electronic May include circuits or sequence programs.

The Speed of the spindle is within one of the control device Speed range determined. This is naturally limited. Occasionally, for example for very small tool diameter or other reasons, speeds demanded the outside the speed range of the spindle are.

From the DE 298 12 170 U1 Further, a motor spindle is known, which is used in CNC-controlled machine tools for performing machining operations. The motor spindle includes a support pin for connection to the machine tool, a housing, an electric motor disposed in the housing, and a spindle adapted to receive a tool or a tool holder. The spindle is formed by the motor shaft of the electric motor, which is rotatably mounted by means of rolling bearings and rotatably connected to the rotor of the electric motor. In addition, a quick-release device is provided, which is operable for clamping or releasing the tool by means of compressed air from the outside.

The Motor spindle is in the tool holder of a machine tool used to use high-speed drivable tools. For this is used instead of the slow-moving main spindle of the machine tool the electric motor is controlled by the CNC control such that the Motor shaft and thus the tool can rotate at high speed. The Using the motor spindle thus requires an intervention in the CNC control of the machine tool, which is not always possible.

outgoing It is the object of the invention to provide a tool drive device to create the scope of a machine tool or Machining unit expanded. This should be possible without interference with the existing machine control happen.

These Task is solved with a tool drive device, the having the features of claim 1.

The Tool drive device according to the invention has a spindle insert, preferably in a machine spindle rotatably clamped and a tool for machining workpieces can carry. The attachment of the spindle insert in the machine spindle serves a coupling device. To drive the tool is in the spindle insert a drive provided from an outside the spindle insert arranged supply source fed and from a control device can be controlled. The feed is over accomplished with the supply lines of the drive connectable coupling agent. The control of the drive takes place according to claim 1 in dependence from the movement of the machine spindle, for the detection of the Werkzeugabreibseinrichtung a Detection device comprises.

From the movement of the spindle is by means of the detection device an example. The speed characterizing signal obtained as Input signal for The control device is used to drive the tool and thus to control its movement. The detection of the speed does not require any access to the machine control, in particular No control signals originating from the machine control are required. The Control device is separated from the other machine control, independently and thus self-sufficient.

To power the electric motor with energy at least one slip ring is provided, which is mounted on the outside of the housing of the spindle insert, electrically isolated from this and connected via a supply line to the drive. The slip ring is in operation with an associated contact, for example. A sliding contact of the coupling means in engagement. During the rotary movement of the machine spindle, the sliding contacts grind on the slip rings and thus ensure the energy supply to the drive. The sliding contacts can also be connected to a drive unit that generates drive signals for the drive. Instead of sliding contacts and roles can be used. The supply can also be non-contact, for example. Transformed.

The Power supply can, if desired, by tapping the Machine control or the supply source of the machine tool done. However, it can also have its own power source for energy be provided.

Both solutions is common that they are the scope of a machine spindle expand. With the tool drive device, it is possible to Speed of the machine spindles over the options to enlarge the machine spindle. Unlike one passive auxiliary transmission can here by the additional power supply in the drive on the tool a total power implemented which exceeds the power of the machine spindle. The maximum torque can completely to be obtained while the speed is increased.

Of the Spindle insert has a coupling device, for. B. a steep taper, on, the safe, non-rotatable and detachable connection with the machine spindle allows. Furthermore he has a substantially cylindrical, one or more parts casing on, in the interior of the drive is arranged.

Should Machining operations are performed with rotating tool, the drive is designed as a rotary drive. For driving the tool then serves an engine, for. B. an electric motor. It can be DC motors, Synchronous or asynchronous motors for single or multi-phase alternating current Find use. It can also hydraulic or pneumatic drives can be used with which rotary or axial movements of the tool can be achieved. The Engines can directly or via a gear drive with the Be connected tool.

at a preferred embodiment The invention is a receiving device for receiving the tool provided, which has a tool spindle into which the tool is clamped rotatably. Inside, the tool spindle preferably the shape of a cone. The tool spindle is then replaced by a rotatably mounted shaft formed and protrudes out of the housing. The shaft is connected to a rotating part of the engine (inside or outside) External rotor) rotationally fixed connected. Preferably, the shaft and the tool spindle are rotationally symmetrical formed to a rotational axis defined by the machine spindle. However, the tool spindle can also be a quick-release, a Chuck and the like wear.

The the power supply serving slip rings are preferably on a cone-shaped Part of the housing arranged, whose diameter increases away from the machine spindle. The slip rings therefore have different diameters. Of the smallest diameter is larger than that of any part of the coupling device. Thereby the spindle insert can be inserted into the machine spindle can change without changing the location of the contact set. This can then be rigid be attached to the machine tool, preferably preferably easily tilted, the slope of the cone-shaped housing part is arranged accordingly. When inserting the spindle insert is the contact between the slip rings and the sliding contacts made by itself. The contact set can also be adjustable and or stored separately.

The Safety of the tool drive device is increased when only during the machining process voltage applied to the sliding contacts. If rotational speeds are detected with the detection device, that are at least as big as a defined threshold, preferably 30 U / min, is, for example. by automatic closing a switch allows the power supply to the sliding contacts. At speeds below the threshold, the circuit is opened.

to Speed detection are non-contact, magnetic or optical methods preferred. It can, for. B. a rotatably connected to the spindle insert or the machine spindle Metal part serve, with each revolution a short voltage pulse to induce in a fixed coil.

In an advantageous embodiment, the detection device a signal generator, in particular a light source, and a signal sensor, in particular a light sensor, on. The detection device is preferably on the machine tool, for example, on which the machine spindle leading Headstock, or the contact set carrier for adjustment adjustable appropriate. On the tool coupling or on the machine spindle becomes a mark, for example a narrow metal plate, attached, the light emitted from the light source reflects. A generated thereby, the speed of the machine spindle characteristic Signal, for example, a pulse signal proportional thereto, then becomes Control device sent.

As a marker can serve a toroidal clamp body having other optical properties, as the point to which it is to be attached. The clamping body may have an interruption or recess. The passage of the Interruption or recess in front of the sensor generates the signal.

It can Furthermore Markers are provided, the more sensor signals at each revolution cause. The markers can evenly spaced in the simplest case and For example, be provided on an adhesive tape.

The Control device uses the incoming from the detection device Signals to generate a corresponding supply signal for the drive. Thus, the speed range of the tool with the device according to the invention be extended. Existing machine tools are thus without Intervention in their mechanics or electronics versatile made.

The Control device can be integrated in the spindle insert or be accommodated separately. You can also by means of appropriate be controlled on a computer running programs. For the user can be a user interface be provided.

Preferably is for cooling of the tool in the tool drive device at least one Supply line for coolant or compressed air and an outwardly leading preferably pivotally arranged nozzle, For example, made of plastic, provided. In addition, it can also be done simultaneously the heat be derived from the tool drive device.

Further advantageous details of embodiments of the invention result from subclaims, the drawing and / or the associated Description.

In the drawing is an embodiment of the Subject of the invention shown. Show it:

1 a tool drive device according to the invention in a partially schematized front view,

2 the front view of the tool drive device 1 in a partly cutaway and partially schematic representation,

3 a side view of the device according to the invention from 1 and 2 used coupling agent in a partially schematized representation,

4 a plan view of the coupling means 1 to 3 in a partially schematic representation, and

5 a schematic representation of the principle of operation of the device according to the invention.

A tool drive device 1 points as they are schematic and in overall view 1 Illustrated is a housing 2 on, which has a substantially approximately cylindrical basic shape. At one end is on the housing 2 a steep taper 3 formed, which is provided for receiving in a corresponding, not further illustrated chuck of a machine spindle. At the steep cone 3 closes a gripping disc 4 at. A short cylindrical section 5 that directly adjoins the gripping disc 4 adjoins, but has a smaller diameter than this, serves as a carrier for brands 6 , the nature and meaning of which will be explained later.

To the cylindrical section 5 then there is a conical connection section 7 formed, whose smallest diameter to the cylindrical portion 5 followed. However, the diameter is here already larger than that of the gripping disc. The conical connection section 7 has one or more, in the present example, three slip rings 8th ( 8a . 8b . 8c ), which is the power supply in the housing 2 accommodated, out 2 apparent drive 9 serve. The slip rings 8th and the mark 6 is a connection head 11 associated with a contact carrier 12 and a sensor unit 14 wearing. The connection head 11 is preferably fixedly mounted on the machine tool, on which the tool drive device 1 to use. Alternatively, the connection head 11 mounted on a support, which causes a radial movement of the connection head 11 allows and this brings only in connection position when the tool drive unit 1 is to be attached to the machine spindle. If other tools are to be used, the connection head can be used 11 then be moved out of the way. However, this is not necessary in most cases.

The tool drive unit 1 points after the conical connection section 7 a cylindrical housing part 15 on, of which of the steep cone 3 far end with a lid 16 is closed. This far a central opening, through which a rotatably mounted spindle 17 protrudes. This is set up to accommodate tools and shows how out 2 emerges, to an inner cone 18 on. The spindle 17 adjacent is a preferably movably mounted nozzle 19 arranged with a channel 21 is in communication, which can serve the supply of cooling lubricant.

How out 2 is apparent in the interior of the housing 2 , Preferably essenli Chen in one of the housing part 15 enclosed interior of the drive 9 in the form of an electric motor 22 arranged. The spindle 17 forms the motor shaft and is at both ends of the electric motor 22 through ball bearings 23 . 24 rotatably mounted. The electric motor 22 may be a servomotor, a stepping motor, a three-phase asynchronous motor, a synchronous motor or any other suitable electric motor. It can be constructed as a disk or bell rotor motor, if low moments of inertia are required. In addition, between the electric motor 22 and the through the inner cone 18 formed clutch for coupling a tool, a transmission, such as a planetary gear, be provided to change the speed, in particular to increase or to generate additional movements, such as Axialbewegun gene. If necessary, this can also be done with other drives.

From the stator 25 of the electric motor 22 starting lead wires 26 to the slip rings 8th that are continuous and concentric to a rotation axis 27 are arranged. Also concentric to this axis of rotation 27 are the steep taper 3 , the case 2 and the spindle 17 arranged.

The connection head 11 is in the 3 and 4 separately illustrated. At its the tool drive device 1 facing side 31 are sliding contacts 32 ( 32a . 32b . 32c ) arranged by springs 33 radially in the direction of an in 4 indicated arrow 34 on the axis of rotation 27 to be biased. The sliding contacts 32 are over lines 35 to a drive unit 36 connected. The drive unit 36 generates drive signals for the drive 9 who in 5 is shown as a block.

The drive unit 36 is also on the sensor head 14 connected and receives from this signals corresponding to the speed of the machine spindle. These are the markings 6 intended ( 1 and 2 ), with the sensor head 14 interact. The markings may include, for example, recesses or projections on the section 5 the tool drive unit 1 be. The sensor head 14 then contains a corresponding detection means for these recesses or projections, for example a magnetic detection device. In the present case, the sensor head is based 14 but on optical principle. A light source 37 illuminates the section 5 and the reflected light is from a sensor 38 registered. The mark 6 has one opposite the other section 5 deviant reflection behavior. For example, the mark 6 be formed by a slotted plastic ring, which forms the section 5 partially engages and leaves between its two opposite free ends a smaller section free, whose passage from the sensor head 14 is detected. This is at each revolution of the machine spindle and thus with each revolution of the tool drive device 1 on the sensor 14 generates a signal. Alternatively, multiple brands may be provided, which then generate multiple signals. As markings 6 If necessary, other means, such as monochrome or marked adhesive tape, may be used instead of the plastic ring.

The drive unit 36 generated at its output 41 Signals the frequency at their input 42 correspond to received signals. The equivalent can be via an operator terminal 43 be determined with which then, for example, can be determined which input speed (input 42 ), which output speed (output 41 ) generated. Alternatively, the correspondence may be fixed or adjustable via a data interface with a computer.

The tool drive device described so far 1 works as follows:
The tool drive device 1 can be kept in the magazine of a machine tool or in a separate storage device. For example, it may be pre-equipped with a tool that with its shaft in the inner cone 8th the spindle 17 is included. To set up for operation with the tool drive device according to the invention 1 is at the machine tool near the spindle at a suitable location of the connection head 11 to assemble. This remains in or on the machine tool. The connection head 11 is arranged at a distance from the work spindle, a free passage of a gripping disc 4 allowed, leaving the connection head 11 the change of a conventional tool is not hindered.

In addition, in or on the machine tool, the control device of the tool drive device 1 assembled. This control device includes the drive unit 36 and any existing control unit 43 , It should now be the tool drive unit 1 operated, this is used as a conventional tool in the machine spindle, that is coupled to this. This is done essentially by an axial movement in the direction of the axis of rotation 27 , The gripping disc 4 goes to the contact head 12 over without touching it. During the steep taper 3 in a corresponding recording, come the contacts 32 of the contact head 12 with the slip rings 8th in touch. In addition, the mark comes 6 into the field of vision of the sensor head 14 ,

At the control unit 43 is now or previously set as the drive 9 , starting from drive pulses, to be controlled by the sensor head 14 to be delivered. For example, a fixed speed ratio can be set. If the speed ratio, for example, on the factor 5 set, rotation of the machine spindle at 100 rpm causes the control unit 36 To deliver pulses for 500 rpm, allowing the drive 9 is controlled accordingly. The speeds then add up, leaving the spindle 17 running at 600 rpm. If the speed of the machine spindle, for example, increased to 5 000 rev / min, the drive 9 with five times the speed, that is driven at 25 000 U / min. These add up to the spindle speed, leaving the spindle 17 ultimately running at 30,000 rpm.

In this way, speeds can be achieved that would otherwise not be accessible to the machine spindle. In addition, through the control unit 43 if necessary, a stepless change in the speed of the spindle 17 be brought about.

Notwithstanding the above-described embodiment, it is possible to leave without the idea of the invention, the drive unit 36 and the control unit 40 in the tool drive unit 1 to integrate. The mark 6 is then stationary outside the tool drive device 1 to install. Instead of the mark 6 is at the tool drive device 1 to provide a corresponding read head. The setting of the control unit 36 takes place, for example, by preprogramming when the tool drive device 1 is separated from the machine tool. It can be provided controls on the tool drive unit or an interface for connecting a computer or other operating unit. In this embodiment, the power supply, as shown 1 or 2 can be seen from the outside.

The above-described embodiments have the advantage that even non-integer speed ratios by appropriate programming of the drive unit 36 are adjustable. If necessary, however, this programmability can be dispensed with. In a simplified embodiment, it is then also possible, for example, a change in speed only by changing the number of on the section 5 existing brands 6 to reach. For this purpose, suitable branded adhesive tape can be used. Also, the marks themselves can be represented by adhesive tape. In all cases, the control of the tool drive device 1 achieved without intervention in the machine control of the machine tool.

A tool drive device 1 , which is particularly intended for machine tools, has an internal drive 9 on, which serves to drive a tool.

There is also a control device 36 provided the movement of the tool drive device 1 recorded and their drive 9 controls accordingly. The control of the tool drive device 1 can thus be done independently of the other control of the machine tool.

Claims (20)

Tool drive device ( 1 ), in particular for machine tools or machining units in machining centers, each having at least one movably mounted machine spindle, with a spindle insert ( 2 ), which can be connected to a machine spindle coupling device ( 3 ), a housing ( 2 ), a controllable drive ( 9 ) for driving a tool adapted to convert its feed energy into mechanical energy and at least one supply line ( 8th ), which is used to transmit the feed energy to the drive ( 9 ) and one or more slip rings ( 8a . 8b . 8c ) located on the outside of the housing ( 2 ) and are electrically isolated from this, with a coupling agent ( 11 ), one or more contacts ( 32 ), which is used to produce or dissolve an energy transferring connection between a supply source and the drive ( 9 ) with the slip ring or rings ( 8th ) and separable from them, and with a control device ( 36 ), which are used to control the drive ( 9 ) is set up. Tool drive device according to claim 1, characterized characterized in that the movement of the machine spindle is a rotary movement is. Tool drive device according to claim 1, characterized in that it comprises a detection device ( 14 ), which serves to detect the movement of the machine spindle. Tool drive device according to claim 1 to 3, characterized in that the control device ( 36 ) is controlled solely by the movement of the machine spindle. Tool drive device according to claim 1, characterized in that the coupling device ( 3 ) is a conical shank, which is clamped in a machine spindle, and that following a subsequent gripping disc ( 4 ) with a designed for automatic tool change gripper groove a cylinder section ( 5 ) as a carrier for a mark ( 6 ) is provided. Tool drive device according to claim 1, characterized in that the drive ( 9 ) serving as a rotary electric motor ( 22 ). Tool drive device according to claim 1, characterized in that the drive ( 9 ) with a receiving device ( 18 ) is drivingly connected to a tool. Tool drive device according to claim 7, characterized in that the receiving device ( 18 ) for the tool at the coupling device ( 3 ) opposite side on a spindle ( 17 ) from the housing ( 2 protrudes and is designed as an inner cone. Tool drive device according to claim 8, characterized in that the spindle ( 17 ) rotationally symmetrical to an axis of rotation defined by the machine spindle ( 27 ) is trained. Tool drive device according to claim 1, characterized in that the slip ring or slip rings ( 8th ) on a conical part ( 7 ) of the housing ( 2 ) is arranged, wherein the diameter of the smallest slip ring ( 8th ) is at least as large as the largest diameter that the tool coupling ( 3 ) or a subsequent gripping disc ( 4 ) having. Tool drive device according to claim 1 or 10, characterized in that the coupling means ( 11 ) essentially a contact set ( 32 ), to which one or more sliding contacts ( 32a . 32b . 32c ) the number of slip rings ( 8th ), which are designed in the form of carbon brushes or brushes or rollers, and via supply line to a supply source and / or control device ( 36 ) are connectable. Tool drive device according to claim 11, characterized in that the contact set ( 32 ) is movably mounted on the machine tool and / or on a spindle bearing the machine spindle. Tool drive device according to claim 3, 11 or 12, characterized in that on the sliding contacts ( 32a . 32b . 32c ) voltage is applied only when with the detection device ( 12 ) a rotational movement of the machine spindle with a minimum number of revolutions of preferably 30 rev / min is detected. Tool drive device according to claim 1, characterized characterized in that the detection of the rotational movement without contact and optically or magnetically. Tool drive device according to claim 14, characterized in that the detection device ( 12 ) a signal generator ( 37 ) for transmitting a signal and a signal receiver ( 38 ) for detecting the same. Tool drive device according to claim 15, characterized in that the signal transmitter ( 37 ) a light source and the signal receiver ( 38 ) is a light sensor. Tool drive device according to claim 16, characterized in that by the signal generator ( 37 ) and the signal receiver ( 38 ) detection device ( 12 ) on the machine tool, for example, on which the machine spindle leading headstock, is mounted adjustable with respect to their height and location. Tool drive device according to claim 17, characterized in that on the machine spindle or on the tool drive device ( 1 ) a reflection medium ( 6 ), such as a wafer or foil, is mounted and oriented to reflect the light emitted by the light source to the sensor. Tool drive device according to claim 17, characterized in that on the tool drive device ( 1 ), on a cylindrical section ( 5 ), a substantially annular, if necessary, provided with an interruption or recess clamp body is attached, which has a surface having different reflective properties than the surface on which it is supported and held. Tool drive device according to claim 1, characterized in that it comprises at least one supply line ( 21 ), which are inside the housing ( 2 ) and substantially pärällel its axis of rotation ( 27 ) is arranged, and an outwardly leading preferably pivotally mounted nozzle ( 19 ), which serve to supply cooling liquid, compressed air or similar medium to the tool.